Biomaterial Database

Biosynthesis of glycosaminoglycans: uridine diphosphate glucose 4'-epimerase from cornea and epiphysial-plate cartilage. 1975

G De Luca, and P Speziale, and C Balduini, and A A Castellani

UDP-glucose 4'-epimerase (EC 5.1.3.2.) was extracted from newborn-pig epiphysial-plate cartilage and whole bovine cornea. The formation of radioactive UDP-galactose from UDP[U-14C]glucose was demonstrated by radioautography after separation of the sugar nucleotides by paper chromatography or t.l.c. The pH optimum and the Km values for UDP-glucose, UDP-galactose and NAD+ were determined in both tissues. UDP-galactose and UDP-glucuronic acid formation after incubation with different UDP-glucose concentrations was followed; the same experiment was carried out using different UDP-galactose concentrations and following the formation of UDP-glucose and UDP-glucuronic acid. At equilibrium, the ratio UDP-glucose/UDP-galactose reaches a value of about 3.5. The results obtained seem to indicate that UDP-glucose 4'-epimerase activity is strongly dependent on that of UDP-glucose dehydrogenase. The physiological meaning of UDP-glucose 4'-epimerase in glycosaminoglycan biosynthesis in the two tissues under study is discussed on the basis of the Km values of UDP-glucose 4'-epimerase and UDP-glucose dehydrogenase and on the basis of the rate of UDP-glucose and UDP-galactose utilization.

UI	MeSH Term	Description	Entries
D007632	Keratan Sulfate	A sulfated mucopolysaccharide initially isolated from bovine cornea. At least two types are known. Type I, found mostly in the cornea, contains D-galactose and D-glucosamine-6-O-sulfate as the repeating unit; type II, found in skeletal tissues, contains D-galactose and D-galactosamine-6-O-sulfate as the repeating unit.	Keratosulfate,Sulfate, Keratan
D002238	Carbohydrate Epimerases	Enzymes that catalyze the epimerization of chiral centers within carbohydrates or their derivatives. EC 5.1.3.	Carbohydrate Isomerases,Epimerases, Carbohydrate,Isomerases, Carbohydrate
D002356	Cartilage	A non-vascular form of connective tissue composed of CHONDROCYTES embedded in a matrix that includes CHONDROITIN SULFATE and various types of FIBRILLAR COLLAGEN. There are three major types: HYALINE CARTILAGE; FIBROCARTILAGE; and ELASTIC CARTILAGE.	Cartilages
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D002809	Chondroitin Sulfates	Derivatives of chondroitin which have a sulfate moiety esterified to the galactosamine moiety of chondroitin. Chondroitin sulfate A, or chondroitin 4-sulfate, and chondroitin sulfate C, or chondroitin 6-sulfate, have the sulfate esterified in the 4- and 6-positions, respectively. Chondroitin sulfate B (beta heparin; DERMATAN SULFATE) is a misnomer and this compound is not a true chondroitin sulfate.	Chondroitin 4-Sulfate,Chondroitin 6-Sulfate,Chondroitin Sulfate A,Chondroitin Sulfate C,Blutal,Chondroitin 4-Sulfate, Aluminum Salt,Chondroitin 4-Sulfate, Potassium Salt,Chondroitin 6-Sulfate, Potassium Salt,Chondroitin 6-Sulfate, Sodium Salt,Chondroitin Sulfate,Chondroitin Sulfate 4-Sulfate, Sodium Salt,Chondroitin Sulfate, Calcium Salt,Chondroitin Sulfate, Iron (+3) Salt,Chondroitin Sulfate, Iron Salt,Chondroitin Sulfate, Potassium Salt,Chondroitin Sulfate, Sodium Salt,Chondroitin Sulfate, Zinc Salt,Chonsurid,Sodium Chondroitin Sulfate,Translagen,Chondroitin 4 Sulfate,Chondroitin 4 Sulfate, Aluminum Salt,Chondroitin 4 Sulfate, Potassium Salt,Chondroitin 6 Sulfate,Chondroitin 6 Sulfate, Potassium Salt,Chondroitin 6 Sulfate, Sodium Salt,Chondroitin Sulfate 4 Sulfate, Sodium Salt,Chondroitin Sulfate, Sodium,Sulfate, Chondroitin,Sulfate, Sodium Chondroitin,Sulfates, Chondroitin
D003315	Cornea	The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed)	Corneas
D006025	Glycosaminoglycans	Heteropolysaccharides which contain an N-acetylated hexosamine in a characteristic repeating disaccharide unit. The repeating structure of each disaccharide involves alternate 1,4- and 1,3-linkages consisting of either N-acetylglucosamine (see ACETYLGLUCOSAMINE) or N-acetylgalactosamine (see ACETYLGALACTOSAMINE).	Glycosaminoglycan,Mucopolysaccharides
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog
D014534	UDPglucose 4-Epimerase	A necessary enzyme in the metabolism of galactose. It reversibly catalyzes the conversion of UDPglucose to UDPgalactose. NAD+ is an essential component for enzymatic activity. EC 5.1.3.2.	UDP Galactose Epimerase,UDP Glucose Epimerase,UDPgalactose 4-Epimerase,Uridine Diphosphate Glucose Epimerase,UDP-Galactose 4-Epimerase,UDP-Glucose 4-Epimerase,4-Epimerase, UDP-Galactose,4-Epimerase, UDP-Glucose,4-Epimerase, UDPgalactose,4-Epimerase, UDPglucose,Epimerase, UDP Galactose,Epimerase, UDP Glucose,Galactose Epimerase, UDP,Glucose Epimerase, UDP,UDP Galactose 4 Epimerase,UDP Glucose 4 Epimerase,UDPgalactose 4 Epimerase,UDPglucose 4 Epimerase